2019/06/19 by S. Lacaprara, Lacaprara, Stefano
Physics and Astronomy · #Dark Matter and Cosmic Phenomena #FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #Particle Detector Development and Performance #Particle physics theoretical and experimental studies
paper · pdf · doi:10.48550/arxiv.1906.08013
openalex publication_date 2019/06/19 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Time dependent CP-violation phenomena are a powerful tool to precisely measure fundamental parameters of the Standard Model and search for New Physics. The Belle II experiment at the SuperKEKB energy-asymmetric e+e- collider is a substantial upgrade of the B factory facility at the Japanese KEK laboratory. The design luminosity of the machine is 8×1035~cm-2s-1 and the Belle II experiment aims to record 50~ab-1 of data, a factor of 50 more than its predecessor. From February to July 2018, the machine has completed a commissioning run, achieved a peak luminosity of 5.5×1033~cm-2s-1 , and Belle II has recorded a data sample of about 0.5~fb-1 . Main operation of SuperKEKB has started in March 2019. This early data set is used to establish the performance of the detector in terms of reconstruction efficiency of final states of interest for the measurement of time dependent CP violation, such as J/ψK0 , η' K0, and ϕK0. A first assessment of the B flavor tagging capabilities of the experiment will be given, along with estimates of the Belle II sensitivity to the CKM angles ϕ1/β and ϕ2/α and to potential New Physics contributions in penguin amplitudes dominated decays and in b→ sγ transitions. In this paper we will present estimates of the sensitivity to ϕ1 in the golden channels b→ cc s and in the penguin-dominated modes B0→ η' K0, ϕK0, K0π0(γ). A study for the time-dependent analysis of B0→π0π0, relevant for the measurement of ϕ2, and feasible only in the clean environment of an e+e- collider, will also be given.